Figure 9 .

Charge-induced differences in uptake. Incubation of NR-MSPs in HeLa cells at a low concentration (1 μg/ml), NR-MSP (green, 83.6%), NR-MSP-PEI-ACA (red, 62.4%), NR-MSP-PEI-SUCC (orange, 69.6%), NR-MSP-PEI adsorbed (light blue, 93.2%), NR-MSP-PEI grafted (teal, 97.9%) and control (violet).